Drinking Water

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General Overview

The Drinking Water page is intended to serve as a means of providing the relevant information to the users who wish to perform a QMRA on drinking water

Tap Water Consumption

Table 1: Estimated Combined Directa & Indirectb Community Water Ingestion via EPA Exposure Factors Handbook
Population Age Number of Subjects Mean (90% CI) c (mL/person/day) 95th (90% BI) d (mL/person/day)
United States People Birth to <1 month 91 184 (117-251) 839 (638-859)
1 to <3 months 253 227 (180-274) 896 (878-1022)
3 to <6 months 428 362 (322-401) 1056 (1043-1170)
6 to <12 months 714 360 (328-392) 1055 (1008-1254)
1 to <2 years 1040 271 (253-289) 837 (754-925)
2 to <3 years 1056 317 (298-337) 877 (828-939)
3 to <6 years 4391 380 (365-394) 1078 (1053-1109)
6 to <11 years 1670 447 (417-476) 1235 (1148-1317)
11 to <16 years 1005 606 (562-651) 1727 (1615-1780)
16 to <18 years 363 731 (633-828) 1983 (1843-2128)
18 to <21 years 389 826 (746-906) 2540 (1908-2934)
>21 years 9207 1104 (1074-1134) 2811 (2732-2924)
>65 years 2170 1127 (1073-1180) 2551 (2500-2637)
All ages 20,607 926 (903-949) 2544 (2500-2584)

a Direct water: water ingested directly as a beverage.
b Indirect water: water added in preparation of food or beverages.
c 90% CI: 90% confidence interval about the estimated means.
d 90% BI: 90% bootstrap interval about the estimated percentiles.
Source of data: 1994-1996 and 1998 USDA Continuing Survey of Food Intakes by Individuals (CSFII).
(Kahn H.D. and Stralka K., 2009)

Water Distribution Fate and Transport

Treatment

Engineering Controls

Disinfection

Chlorine

Table 1. Reduction Value (log10) by free chlorine
Type of Treatment Protozoa Bacteria Viruses
Baselinea Maximumb Baseline Maximum Baseline Maximum
free chlorine 3 5 3 6 3 6

aexpected in actual field practice when done by relatively unskilled persons who apply the treatment to waters of varying quality and where there are minimum facilities or supporting instruments;
bby skilled operators who are supported with instrumentation and other tools to maintain the highest level of performance in waters of predictable and unchanging quality.
(Sobsey et al. 2008)

UV

Filtration

Table 2. Reduction Value (log10) by Filtration
Type of Filtration Protozoa Bacteria Viruses
Baseline Maximum Baseline Maximum Baseline Maximum
Porous ceramic filtration 4 6 2 6 0.5 4
Biosand filtration 2 4 1 3 0.5 3

(Sobsey et al. 2008)


Pathogen Occurrence in Water Sources

Sewage

Surface Water

Ground Water

Table 1. Pathogens in Groundwater

Pathogen Location Presence/Absence Concentration a Note References
Total Cultural Enteric Viruses
(BGM b)
Missoula, MT
Eight Wells from Unconfined Aquifer
n = 7
 % positive = 0
Min: < 0.67
Max: < 4.05
Avg: < 1.74
Std: < 1.43
Unit: MPN/1000L
Water samples from wells beneath and adjacent to the
drainfield of the septic tanks were collected.
Please see the virus data in septic tanks in Table Y.
DeBorde et al, 1998
Total Cultural Enteric Viruses
(BGM b)
Nottingham and Birmingham, UK
Sandstone Aquifers
n = 107
 % positive = 10
Detection limit: 1000
Min: 5000
Max: 10,000
Avg: 1382
Std: 1670
Unit: PFU/1000L
Only two quantifiable samples were found. Powell et al, 2003
Six virus groups c
(qRT-PCR)
Madison, WI
Six municipal water-supply wells
n = 147
 % positive = 47
Max: 6.27
Avg: 0.65
Unit: Gene Copies/L
Bradbury et al, 2010
Five virus groups d
(RT-PCR)
La Crosse, WI
Six drinking-water supply wells
n = 48
 % positive = 50
Borchardt et al, 2004
Five virus groups d
(RT-PCR)
Madison, WI
Three wells from confined bedrock aquifer
n = 30
 % positive = 23
Borchardt et al, 2007
Five virus groups d
(RT-PCR)
Wisconsin
Fifty household wells
n = 194
 % positive = 2.6
Borchardt et al, 2003
Four virus groups e
(RT-PCR)
United States
n = 448
 % positive = 31.5
Abbaszadegan et al, 2003
Infectious enteroviruses
(Cell culture)
United States
n = 442
 % positive = 4.8
Abbaszadegan et al, 2003

a: All averages included negative samples reported at detection limit
b: Cell culture line
c: Enteroviruses, adenoviruses, rotavirus, hepatitis A virus (HAV), and norovirus genogroups I and II
d: Enteroviruses, rotavirus, hepatitis A virus, and norovirus genogroups I and II
e: Enteroviruses, rotavirus, hepatitis A virus, and norwalk virus

Treated Water

Distribution Systems

Pathogen Specific

Dose Response

Pathogens with oral data available

Campylobacter (human)
Cryptosporidium (human)
Echovirus (human)
Entamoeba coli (human)
Enteroviruses
Escherichia coli (human)
enterohemorrhagic Escherichia coli
Francisella tularensis
Giardia (human and animals)
Rhinovirus (human)
Shigella species (human)
Vibrio cholera (human)

Survival

Transport

References

Abbaszadegan M, Lechevallier M and Gerba C. (2003) Occurrence of viruses in US groundwaters. Journal AWWA. 95(9): 107-120. Full text

Borchardt M., Bertz, P., Spencer, S. and Battigelli, D. (2003) Incidence of Enteric Viruses in Groundwater from Household Wells in Wisconsin. Applied and Environmental Microbiology. 69(2): 1172–1180. Full text

Borchardt M., Bradbury, K., Gotknowitz, M., Cherry, J. and Parker, B. (2007) Human Enteric Viruses in Groundwater from a Confined Bedrock Aquifer. Environmental Science & Technology. 41, 6606-6612. Full text

Borchardt M., Haas N and Hunt R. (2004) Vulnerability of drinking-water wells in La Crosse, Wisconsin, to enteric-virus contamination from surface water contributions. Applied and Environmental Microbiology. 70(10): 5937-5946. Full text

Bradbury K, Borchardt M, Gotkowitz M and Spencer S. (2010) Human viruses as tracers of wastewater pathways into deep municipal wells. Final report to the Wisconsin Department of Natural Resources.

DeBorde D, Woessner W, Lauerman B and Ball P. (1998) Virus occurrence and transport in a school septic system and unconfined aquifer. Ground Water. 36(5): 825-834. Full text

EPA Exposure Factors Handbook

Kahn H. and Stralka K. (2009) Estimated daily average per capita water ingestion by child and adult age categories based on USDA's 1994-1996 and 1998 continuing survey of food intakes by individuals. Journal of Exposure Science and Environmental Epidemiology 19, 396-404 Full text

Powell K, Taylor R, Cronin A, Barrett M, Pedley S, Sellwood J, Trowsdale S and Lerner D. (2003) Microbial contamination of two urban sandstone aquifers in the UK. Water Research. 37: 339-352. Full text

Sobsey, M., Stauber, C., Casanova, L., Brown, J. and Elliott, M. (2008) Point of use household drinking water filtration: A practical, effective solution for providing sustained access to safe drinking water in the developing world. Environmental Science & Technology 42, 4261-4267. Full text